Delphinium tricorne

Species Native to Missouri
Common Name: dwarf larkspur 
Type: Herbaceous perennial
Family: Ranunculaceae
Native Range: Eastern United States
Zone: 4 to 7
Height: 1.00 to 2.00 feet
Spread: 0.75 to 1.50 feet
Bloom Time: April to May
Bloom Description: Violet blue to purple (occasionally with white)
Sun: Full sun
Water: Medium
Maintenance: Medium
Flower: Showy
Attracts: Hummingbirds, Butterflies
Tolerate: Rabbit, Deer

Culture

Winter hardy to USDA Zones 4-7 where this delphinium is best grown in fertile, humus rich, medium moisture, well-drained soils in full sun. Performs well in alkaline soils. Appreciates some part afternoon sun-dappled shade in hot summer climates. Prefers climates with cool summer temperatures. Plants sometimes struggle in St. Louis summers, and are generally not recommended for growing in hot and humid summer climates south of USDA Zone 7. Plants are best grown in areas protected from strong winds and rain storms. Plants may be grown from seed and may self-seed in the garden.

Noteworthy Characteristics

Delphinium tricorne, commonly known as dwarf larkspur or spring larkspur, is an herbaceous perennial of the buttercup family that is native to moist rich woods, thickets, ravines, wooded rocky slopes, and cliffs from Pennsylvania to Minnesota south to Oklahoma and Georgia. Each plant features a basal cluster of long petioled grayish-green leaves (to 4” wide), each leaf being palmately cleft into 5 deeply cut lobes with each lobe being further divided into 2-3 secondary lobes (or deeply palmately cut into into narrow lobes). A sparsely-leaved flowering stalk clad with small alternate leaves and topped by a stately terminal spire typically containing 6-14 blue-violet spurred flowers rises from the basal leaf cluster in an April-May bloom which occurs at a tune when the flower stalk has risen to about 12” tall. Plants continue to grow upward after bloom, eventually reaching 18-24” tall. Each flower (to 1 1/2” long) has 5 petal-like sepals and 4 petals. Sepals are usually violet blue to purple, but sometimes variegated with white. The upper sepal of each flower forms a long upright backward projecting spur as described by the common name of larkspur. The four petals are very small. Fruit is a seedpod which separates into 3 parts, with the dried ends extending upward in a manner reminiscent of horns.

Genus name comes from the Greek word delphis meaning dolphin in reference to the flower bud shape of some species purportedly resembling a dolphin.

Specific epithet means three-horned in reference to the three-horned fruits.

Problems

Delphiniums require considerable maintenance (staking, pruning, deadheading, disease control) in order to perform well in the garden. Delphiniums are generally susceptible to powdery mildew, botrytis blight, leaf spots and crown rot. Plants grown in full sun generally show better resistance to powdery mildew. Water plants at the base to avoid wetting the foliage. Crown rot will inevitably develop if plants are grown in poorly drained soils or planted too deep. Slugs and snails can do significant damage. Watch for aphids, leaf miners, stem borers and mites. Taller plants may need staking and appreciate being sited in locations protected from wind. Plants are considered toxic to humans if ingested.

Garden Uses

Superb in cottage gardens. Beds and borders. Best in groupings or massed. Plant against a stockade fence for protection from wind. Excellent cut flower.